Method of and apparatus for filtering oil



Patented Feb. 10, 194@ METHOD OF AND APPARATUS FOR FETERING OIL Ulric B. Bray, Palos Verdes Estates, and John K.

Russell, Los Angelcs, .Calif.

No Drawing. ApplicationMay '31, 1941,

Serial No. 396,145

Qur invention relates to the treatment of hydrocarbon oils such as are employed in the lubricating systems of internalcombustion engines, including Diesel engines and gasoline engines employed in passenger vehicles and the like; Certain aspects of the invention herein disclosed but not claimed arcclaimed in our co-pending application Serial No. 396,144.- 1 t some such lubricating oilsemployed in Diesel and other engines are compounded so that they are alkaline and/or contain oxidation inhibitors to prevent the accumulation of harmful amounts of acid therein during the effective life 'of the oil. -Our invention finds particular utility in the filtering and purifying of such compounded oil in the lubricating system of an internal combustion engine, and without limiting our invention to this use the application of our invention relates to a lubricating system of an internal combustion engine containing such a compounded oil, which will be hereinafter described to illustrate its features and advantages. Likewise, lubricating oils, whether so compounded or not, commonly contain a detergent carried with the oil through the oil circulating system of the engine during the o p'emubn of the engine and acting to remove frcmthe bearing surfaces, rings, and cylinder and'piston walls andto causeto be carried away from such lubricated parts impurities, which otherwisewould accumulate thereon increasing friction and diminishing the eificiency tem, the lubricating oil becomes contaminated withimpurities, some of which are cf. such par ticle size as to be readily removed by the passage ofthe oil containing them through a conventional" filter employing as a straining medium cotton Waste or the like. Others" of these impurities are so finely'divided as to remain suspended in the oil during its passage through such a conventional filter,- and it iswith such suspended impurities thatour invention is principally concerned! Such suspended impurities include; particles of soot.-caused by the combustion of the -f uel,whichaccunnuate in the kill and deposit upon th bear- 8 Claims.' (01. 252-426) ing surfaces, piston rings, and piston and cylinder walls, forming with various impurities accumulating in the oil from the breakdown of the oila hard varnish-like deposit "diminishing the clearance between moving parts and causing the piston rings to stick and friction within the engine to be greatly increased. Such suspended impurities include also suspended and colloidal carbon accumulating in the oil from the breakdown of the oil and also fine particles of silica, dust, and other abrasives from the air.

It is known that the detergents commonly employed in lubricating oil in the circulating systerns of internal combustion engines have the property of removing such suspended impurities from the bearing surfaces, piston rings, cylinder and piston walls, and surfaces with which the oil bearing the detergent contacts, thus preventing their accumulation upon such surfaces, and by the term suspended impurities is meant all such impurities, the accumulation of which upon such surfaces is prevented by a detergent carried by the lubricating oil.

Detergents known to possess such properties include calcium phenylstearate, calcium dichlorostearate, calcium soaps of oxidized petroleum acids such as calcium 'Alox, calcium salts of phenolic bodies, and calcium salts of alkylated phosphoric acid. By the term detergent is meant those substances which may be carried by the oil in the circulating system of an internal combustion engine and which possess a, property for removing impurities from and preventing their accumulation upon surfaces with which the oil bearing such material comes in contact, like that property possessed by those materials specifically identified.

We have found that, when there is employed in the oil circulating system of an internal combustion engine containing oil carrying such a detergent a filter or straining device of conventional construction, the detergent exerts its property of preventing the accumulation of impuritiesin and washing impurities from the filtering or straining medium of the filter device as well as the engine surfaces with which it comes in contact, with the result that the efficiency of the filter is impaired, the accumulation of such im,- purities in the oil stream is rapid, the detergent in the oil is rapidly consumed, and the life of the oil between drains of the system is relatively short.

An objectof our invention is to prevent the removal by the detergent in the oil from the filter or straining device in the oil circulating 3 system of an engine of impurities deposited therein and to cause the deposition in such a filter 01' straining device of the suspended impurities in the oil stream. More specifically, it is an object of our invention to remove and entrap in a filtering device in the oil circulating system of an engine suspended impurities at substantially the rate at which they are formed in the oil stream.

As the detergent carried by the oil in the circulating system in an engine removes the impurities from the surfaces upon which theyare deposited, the detergent in the oil becomes exhausted, and the capacity of the oil for washing and cleansing such surfaces steadily decreases. It is possible that this fact is due to the formation by the detergent in the oil stream of-an envelope around each particle of the suspended impurities, which causes its separation from'the surface upon which it has been deposited and its transportation in the oil stream away from such surfaces, so that the detergent from such envelopes is consumed or rendered ineffective, and the cleaning property of the oil is decreased.

It is an object of our invention to remove from oil bearing a detergent in the oil circulating system of an engine suspended impurities taken from the surfaces contacted by the oil stream by the action of the detergent without removing from the oil stream the detergent and while retaining substantially constant the concentration of the detergent in the oil stream.

This object we accomplish by placing within the oil circulating system of an engine a supply of a material capable of agglomerating the particles of suspended impurities removed from the bearing surfaces by the action of the detergent in the oil until the oil is conditioned for filtration or straining. By conditioning the oil for filtration or straining, we mean agglomerating particles, themselves of such small size as to pass with the oil through the filtering medium in the presence of the detergent, into such a size or mass as to permit the filtering or straining me dium to entrap and retain them.

Since such an agglomerating material is consumed in performing such action, it is an object of our invention to provide in the oil circulating system of an engine a supply of an agglomerating material, the solubility of which is small enough that a supply of practical dimensions will, without exhaustion during the entire period between oil drains, provide a concentration of the material in solution in the oil insufficient to exert a harmful effect upon the engine parts or the cleansing function of the detergent, and the solubility of which is great enough to maintain the concentration of the material in solution in the oil at that value sufficient to agglomerate and thus cause the removal of the suspended impurities at substantially the rate at which they are formed.

If the agglomerating material functions only while the oil bearing the suspended impurities is present in the filtering medium, it will be seen that the time within which the agglomerating action must take place is extremely small as compared with the time required for the oil to circulate through the engine and circulating system, and hence the surface area of the agglomerating material available for contact with the suspended impurities, being all within the filtering medium, controls the dimensions of the filtering medium and requires frequently for effective agglomeration a filteringmedium of very 'agglomerating materialrequired in the filtering medium and consequently reducing the dimensions of the filtering medium required for efiective agglomeration.

Further, it is an object of our invention to condition the oil for filtration or straining to a substantial degree while the oil is in the engine and circulating system outside of the filtering medium connected thereto, so that, when the Soil enters the filtering medium, a substantial proportion of it is immediately capable of filtration 'l toreinove the agglomerated suspended impurities.

We have found that soaps of alkylolamines such as triethanolamine and tri-isopropanolamine areadmirably suited for use as such agglomerating materials. The soaps of alkylamines or arylamines which are sufficiently alkalineto form a soap with an organic acid can be employed.

While any alkylolamine may be employed, we prefer to employ a soap of triethanolamine. The triethanolamine is mixed with a fatty acid having the formula in which a: is more than ten, for example, coconut oil fatty acid or hydroxylated fatty acids, for example, castor oil fatty acid, forming neutral soap so that the mixture does not react alkaline to phenolphthalein.

' Such soaps, of which the foregoing are examples and which may be described as agglomerating soaps of limited solubility, may then be heated to liquefaction and sprayed or sprinkled upon a carrier or supporting medium. Such a supporting medium may be in the form of a fibrous material, such as wool, cotton waste, pounded paper, or paper pulp, or in the form of porous particles, such as pressed or ground walnut hulls, ground coconut shells, sawdust, or the like, or substantially nonporous particles, such as quartz or sand particles or the like. We prefer to utilize as a supporting medium a material capable of exerting a filtering or straining action accomplishing the removal of solid impurities and the agglomerated suspended impurities in the oil stream during its passage therethrough.

We have found cotton waste admirably suited for this purpose, The quantity of cotton waste to be employed is determined by the quantity of impurities which it is desired to remove from the oil circulating system before replacement of the filter unit. If it is desired to replace the filtering or straining medium of the filter unit on each occasion when the oil is drained, we have found, for example, that approximately 500 grams of cotton waste will provide the desired filtering action for the required length of time in the circulating system of a small size Diesel engine used upon a tractor for drawing a ground working implement, where the oil is subjected to a high rate of contamination by dust particles and the li e.

I Likewise, the quantity of agglomerated soap of limited solubility placed on the supportingine-v dium determined by the quantity of suspended particles which the filtering medium is required.

to remove between renewal 'of the filtering me.-

' the"- bearinglsurfaces in thesystem.

cottpnpwaste so coated or .impreenatedvwithzthe agglomerating soap of limited SOIHbiIiFYJfDI'nBXi-r ample. acoconutoiliatty a idsoaptof t than ln. iisicompressedin a :containenplacedimthe mating system of theengine thecomprese sionibeing :to such a degree that gthfi fibres of-tthe' ootti lswaste are: in; such proximity: to each other asito. effectively entrap and .retain solid impuri! tiesjinr the ,oilstream. and the. aggiomeratedbodies of suspended particles :carried thereto by .the oil stream. i V

very small portion. ofethe agglomeratingsoap immediately passes into solution in the oil stream, travelling ,with .it and-the detergent carried bythe streamthrough the system and adjacent the bearing surfaces. The detergent, .loosening fromthe bearing-surfacesparticles of the character of the suspended impurities and, .we believe, forming an envelopearoundeach such particle, carries them to :.the filterunit where they enter the cotton waste. Alsowcarrie'd bylthe oilstream-tothe -c013- tonwwaste are the solidi impurities which 7 are entrapped and retained' therein. The suspended impurities, con-tacting-in-the cotton waste the-cg giomerating isoa-p, either in solution in "the oil stream or supported upon the cotton waste, are caused to agglomerate or accumulate until they form bodieseof sufiicient size to be entrapped and retainediby themcotton waste. This agglomeration or accretion o-E-thesuspended particles is accompanied by a consumption ofthe agglomeratin material of limited solubility, and, as this agglomeratingmaterialin solution in the oil stream is thus consumed; it is replaced by the entry into solution in the ell stream of someof the agglomerating material supported upon thecotton waste, that the concentration of the ;agglomeratirig material in solution in the oil .stream'remains substantially constant.

This agglomeration, entrapment, and retention of the suspended particlesin the filter unitis-not accompaniedby any substantial decrease in the concentrationoi the .detergent in the oil, the-presence and'pon'sumption of theagglomerating matierialoi limitedsolubility apparently preventing such ,a decrease. It is our belief that the suspended particles in their envelopes of the} detcrgent areicaused to :agglomerate by the triethanolamine soap, and in such agglomeration the detergent is freed from the particles and returned lto' the .oil stream free :of them, so that ittmayi repeat its. cleansing oi -washing action; aecomplishingllthe .removal of deposited impurities dirthe character of the suspended :impuritiesirom i limited amount of the agglomerating soap, being dissolved in the--oi1- stream,- exerts -its effect throughou -all of the oi1-in the-circulating system during all of the time that the oil is circulating therethrough, with the result that between the time the colloidal impurities are created in the oil system by use in the engine or washed from the bearing surfaces by the detergent and the time teams I cotton waste in the filter unit contacted py the on streamflhus the 1 o 1 co tinu. i s reassess through thezfi ter n c nt i g aeeiome a' s soap re orted pon t e c tto waste so :'.:i .e,=.fllt.r@h n. r s rain n ,Qf h aee1omer.. d3. esof suspe ded im t s fo llESzfliliQfl 0 he e t e filt r m Triethaid mine alone may bp aoedl pon the set? ewas e eiilternmtand willthere-e ert om ;a lomerat ns a ti .a u sin e t i tha olr. amine has a very much lesser solubility in oil than the lomeratine soansdesmibed herein,,':t conditioning of: th g ilin the en in and circ latns sys em prio to its entry in o he filterin unit W 11,; l0,t .b@; omplished t ny appre iable eereeiand,therefore the; p ons ofthecotton wast first-contacted by the .oil ream r input o erat to nt ap nderetaina lomera bo ies f suspended inertia-lee and. all of suchefi tration' s necessarilyperiormed by the portions oi -th cotton Wasteiater conta tedebr he oil stream within the unit. Furthermore, .sincegthe solubility of triethanolsamine is so muchJQSs: in the oilthan the age'lom crating soaps, described herein, the detergentsare t reed y the triethanolamineto any, appreL-I' ciable extent f-rom.=the suspended particles. in the oilstream'in theeneine; and circulatin y tem as is-the casetwhen the asel m ratmg soaps described are employed. 7 While the absolute sold,- bilities in oil Of triethanolamine and.-the,agglom.-..- crating soaps therein contemplated aredifiicult of determination, beingof :the order :of .a ten thousandths, of one-per cent, the r re a iv ls bilities 111 0 are.moreireadilydetermined, andxwehaveioundthat theagglomerating soaps oft-he characterher inref rred team in ral three or .imoregti-mestas; soluble. as triethanolamine.

:Thevery; substantial increase in volume ofthe soap -made withxti iethanolamine over the 1313i ethanolamine employed permits the distribution oi.the.triethanolarr 1 ine soap much more ,uniform-. 1y: ianda-easily over @the; entire bulk; of the cotton waste .or other. filtering medium, thus. insuring .a uniformity of the agglomerating action through out the ,en-tire'bodyof cottonwaste and a uniform" filtering action throughout the wasteand. hence amaximumfilteringlife for the waste. 1 i

.-As ;previously pointed out, our invention .is "of particular iutility: inlconnection with theoil cir? culating; systems ofu1i3iese1 engines employing 1a" compounded-oil containing alkalineqnaintaining or oxidatiominhibitingmaterials and a detergent.

:As ::will-be.;seenstrum-the foregoing, our invent-. tion contemplates the cleansingfrom the bearing surfaces ofdeposited'impurities and the agglom eration .of such removed impurities and suspendedimpurities .to. bodies .of .suflicient .sizeto be filtered from the oil stream -at -.substantia1ly the .rate :a-t whichpthey. alfeeforrneditherein, the 1 aceomplishe ment. of such ;removal,:,agglomeration, .andfiltrae tion without substantial diminution of the deter! gent or cleansing agent in the oil stream, the simultaneous removal of such impurities from the bearing surfaces and agglomeration of the removed and suspended impurities in the oil in the circulating system of the engine preparatory to the step of filtering the agglomerated bodies from the oil in the, system and the maintenance of the rate of agglomeration at the desired substantially constant value between drains of the oil circulating-system.

While the foregoing examples of materials are sufliciently capable of erformin the objects and providing the advantages or the method and filter of our invention, and while the application of our invention to the oils and engines hereinbeforereferred to are illustrative of the oils and engines with which our invention may be advantageously employed, we Wishour invention tobe understood to be not restricted to the materials herein'before specified or to use with the oils and engines hereinbefore referred to for illustrative purposes, but as including all of the materials and for the uses coming within-the'scope of the claims which follow.

We claim as our invention:

1. The method of treating a flowing stream of substantially non-acidic lubricating oil during contamination by suspended impurities of a particle size insufficient for filtration, which includes the steps of: agglomerating such impurities along the oil stream at substantially the rate at which they are suspended in the oil to bodies of dimensions suflicient for removal-by filtration with an agglomerating amino soap of castor oil fatty acids and having slight solubility in the oil; separating said agglomerated bodies from the lubricating oil at substantially the rate at which such bodies are formed by passing the oil containing such bodies through a filter interposed in the stream; and maintaining'the quantity of theagglomerating soap in solution in the oil substantially constant by replenishing the soap in solution in the oil at the rate it is removed therefrom by the agglomeration of such suspended impurities.

2. The method of treating a flowing stream of substantially non-acidic lubricating oil containin :a detergent during contamination by colloidal impurities, which includes the steps of: conditionting the oil for filtration by agglomerating the colloidal impurities suspended in the oil'along the stream with a castor oil fatty acid soap of triethanolamine; filtering said agglomerated bodies from the oil; and maintaining the concentration of said soap in solution in the oil substantially constant at a value preventing the accumulation of colloidal impurities in the oil by replenishing the soap in solution in the oil, simultaneously with the filtration of the oil, at the rate it is re-. moved from the oil by the agglomeration of the colloidal impurities. r

3. A filter adapted for treating an oil during contamination by particles of solid impurities and colloidal impurities of smaller size than said par of contamination of the oil by said colloidal im-' purities during the efiective life of said filter mass. V

8 4. A filter adapted fortreating an oil during contamination by particles of solid impurities and colloidal impurities of smaller size than said particles, comprising: a filter mass of such porosity asto'allow the oil and colloidal impurities to pass therethrough and to filter the solid particles therefrom; and an agglomerating castor oil soap 0f triethanolamine carried by said filter mass in a quantity sufiicient to agglomerate said colloidal impurities to bodies of dimensions filtered from the oil by said filter mass at substantially the. rate of contamination of the oil by said colloidal impurities during the effective life of said filter mass.

Y .5; A filter adapted for treating an oil during contamination by particles of solid impurities and colloidal impurities ofsmaller size than said particles, comprising: a filter mass of such porosity as to allow the oil and colloidal impurities to pass therethrough and to filter the solid particles therefrom; and an agglomerating hydroxylated fatty acid soap of an alkylolamine carried by said filter mass in a quantity suflicient to agglomerate said colloidal impurities to bodies of dimensions filtered from the oil by said filter mass at substantially the rate of contamination of the oil by said colloidal impurities during the effective life of said filter mass.

6. A process for treating mineral lubricating oil as it is used, said oil containing a detergent material, the process comprising: circulating said used oil; dissolving in said oil a slightly oil-soluble agglomerating amino soap of castor oil fatty acids, said soap being capable ofagglomerating REFERENCES CITED The following references are of record in the file of this patent:

I UNITED STATES PATENTS Number Name Date 1,882,002 Dietrich Oct. 11, 1932 1,914,999 Maverick June 20, 1933 2,081,075 Vobach May 18, 1937 2,093,430 Franklin Sept. 21, 1937 2,095,538 Vobach Oct, 12, 1937 2,133,359 Miller Oct. 18, 1938 2,157,223 Sutton May 9, 1939 2,202,806 Alton May 28,1940 2,208,507 Blair et a1. July 16, 1940 2,302,552 Johnson Nov, 17, 1942 2,303,546 Greger Dec, 1, 1942 2,305,464 Ashworth Dec. 15, 1942 2,306,325 Allamet al Dec. 22, 1942 2,310,305 Miller et al. Feb. 9, 1943 2,320,106 South May 25, 1943 2,321,884 Allam June 15, 1943 2,343,435 Wells et al Mar. 7, 1944 

